In a typical cellular wireless network, an area is divided geographically into a number of coverage areas, such as cells and sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS). Within each coverage area, the BTS's RF radiation pattern provides an air interface over which mobile stations (such as cellular telephones, personal digital assistants (PDAs), and wirelessly-equipped personal computers) may communicate with the cellular wireless network. In turn, the cellular wireless network may communicate with one or more other networks, such as the public switched telephone network (PSTN) or the Internet. As such, when a mobile station is positioned within a coverage area of the cellular wireless network, the mobile station can communicate with entities on the other networks via the cellular wireless network.
The RF air interfaces may carry communications between mobile stations and the cellular wireless network according to any of a variety of protocols. Depending on the protocol employed, the RF air interface of each coverage area in the cellular wireless network may be divided into a plurality of channels for carrying communications between mobile stations and the cellular wireless network. For example, the RF air interface may include a plurality of forward-link channels, such as pilot channels, sync channels, paging channels, control channels, and forward-traffic channels, for carrying communications from the cellular wireless network to the mobile stations. As another example, the RF air interface may include a plurality of reverse-link channels, such as access channels and reverse-traffic channels, for carrying communications from the mobile stations to the cellular wireless network. In some configurations, the cellular wireless network may monitor loading on a given coverage area's reverse link and then provide an indication of this loading to mobile stations in the given coverage area.
Typically, a mobile station begins transmitting new data at a minimum available reverse-link data rate (i.e., a minimum reverse-link data rate supported by the protocol being employed). Thereafter, a mobile station may adjust its reverse-link data rate based on the loading on the given coverage area's reverse link, as indicated by the cellular wireless network. In particular, if the mobile station detects an indication of a lower load on the given coverage area's reverse link, the mobile station may increase its reverse-link data rate (assuming the mobile station is not transmitting at a maximum available reverse-link data rate). If the mobile station detects an indication of a higher load on the given coverage area's reverse link, the mobile station may decrease its reverse-link data rate (assuming the mobile station is not transmitting at a minimum available reverse-link data rate). The mobile station may continue adjusting its reverse-link data rate in this manner until it finishes sending the data, after which the mobile station may reset its reverse-link data rate to the minimum available reverse-link data rate.